[Boost-users] [random] number of seed values required to seed engine

Subject: [Boost-users] [random] number of seed values required to seed engine
From: Thomas Mang (thomasmang.ng_at_[hidden])
Date: 2012-03-27 01:55:23

Hi,

Consider the mersenne_twister_engine<...> member function seeding a 
engine with an iterator range of seed values:

template<typename It> void mersenne_twister_engine<...>::seed(It &, It);

Is there some nice way to figure out how many seed values this function 
will need?

I have used mt19937 and had to inspect the code to figure out it needs 
624. I would find it very useful if this information is somewhere 
readily provided through some organized interface, e.g. a member 
function or a static class member stating that value. Same for other 
engine types.

BTW, I find it surprising that the first parameter is a reference to an 
iterator, and hence the input argument itself will be altered. Is that 
by design? If so what's the rationale? I think it's fairly odd 
behaviour, giving rise to unnecessary dangerousness and should become 
documented more clearly (big warning in bold flashing red letters etc. :) ).

Thanks
Thomas